Sword Art Online(Japanese: ソードアート・オンライン,Hepburn: Sōdo Āto Onrain?) is a Japanese light novel series written by Reki Kawahara and illustrated by abec. The series takes place in the near-future and focuses on various virtual realityMMORPG worlds. The light novels began publication on ASCII Media Works' Dengeki Bunko imprint from April 10, 2009, with a spin-off series launching in October 2012. The series has spawned eight manga adaptations published by ASCII Media Works and Kadokawa. The novels and four of the manga adaptations have been licensed for release in North America by Yen Press.

Sword Art Online has received widespread commercial success, with the light novels having over 16 million copies printed in several countries including Japan, Taiwan, China, South Korea, Thailand, the United States, Canada, and the United Kingdom.[1] The anime series has received mixed to positive reviews from critics, with some praising the exploration of the psychological aspects of virtual reality, while others criticized the series' pacing and writing.

The first virtual game world, and the setting of the first story arc. The world takes the form of a giant floating castle called Aincrad, with 100 floors in it. Each floor has a medieval-themed setting and a dungeon with a boss, which has to be defeated before players can advance to the next higher floor. Like most RPGs, it implements a level-based system. However, after the beta testing, the game's creator activated a system to trap the players inside the game, unable to log out; if players die in-game, or the helmets they used are removed, a strong, electromagnetic pulse is emitted, frying their brain and killing them.

The second virtual game world, and the setting for the second story arc. The player characters in the game are fairy-based, capable of flight thanks to their wings. It is a large world, divided into separate "homelands" for each of its fairy races. In Alfheim's center is a very large tree called the World Tree, and the goal of the game is to reach the top. It implements a skill-based system with players increasing their stats by developing both their combat and non-combat skills. Aincrad, the castle of the first game, is later accessible to ALO players as well.

The third virtual game world, and the setting for the third story arc. It is a virtual game world with a main focus on guns, although melee weapons like lightsabers (photon swords) and knives also exist. From all the games it is the most competitive one as the money earned there can be exchanged for currency used in the real world, drawing high-tier professional players to make a living from it.

The fourth virtual world, and the setting for the fourth arc of the story. It is the first Virtual World setting introduced to not be a game world but rather an AI simulation. According to Kirito, it is graphically the most realistic of all Virtual Worlds to date. The flow of time in UnderWorld is variable and can be much faster relative to the real world's. Kikouka claimed that the current rate of its flow is 1000 times the speed of the real-world, and that the maximum rate was 1500 times the real-world's rate.

Sword Art Online (SAO) is a Virtual Reality Massively Multiplayer Online Role-Playing Game (VRMMORPG), released in 2022. With the Nerve Gear, a virtual reality helmet that stimulates the user's five senses via their brain, players can experience and control their in-game characters with their minds.

On November 6, 2022, the players log into SAO for the first time, and later discover that they are unable to log out. They are then informed by Akihiko Kayaba, SAO's creator, that if they wish to be free, they must reach the 100th floor of the game's tower and defeat the final boss. However, if their avatars die in-game, their bodies will also die in the real world. One of these players is Kazuto "Kirito" Kirigaya, who was chosen as one of the 1,000 beta testers in the closed beta. Since he had previous experience and knowledge of the game, he felt that he could beat the game easily. As a result, he set out to beat the game on his own. As the game progresses for two years, Kirito eventually befriends a female player named Asuna with whom he ultimately falls in love. After the duo discover the identity of Kayaba's avatar in SAO, they confront and destroy him, freeing themselves and the other players from the game.

Upon being sent back to the real world, Kirito learns that 300 SAO players, including Asuna, still have not awakened yet. Following a clue about Asuna's whereabouts in another VRMMORPG called Alfheim Online (ALO), Kirito also enters the ALO's mainframe. Helped by his cousin Suguha Kirigaya, known as Leafa in the game, he learns that the trapped players in ALO are part of a plan conceived by Nobuyuki Sugō to perform illegal experiments on their minds to put them under his control, including Asuna, whom he intends to marry in the real world in order to take over her family's company. After Kirito foils Nobuyuki's plans, he finally reunites with Asuna back in the real world.

Soon after, Kirito plays another game called Gun Gale Online (GGO) to investigate the mysterious connection between it and deaths occurring in the real world. Assisted by a female player he meets in the game called Sinon, he identifies and exposes the culprits, who include some former members of a murderous guild he previously encountered in SAO.

Kirito is later recruited to assist in testing a state-of-the-art FullDive machine, Soul Translator (STL), which has an interface that is far more realistic and complex than the previous machine he had played. He tests the STL by entering a Virtual Reality world created with The Seed package, named UnderWorld (UW). In the UW mainframe, the flow of time proceeds a thousand times faster than in the real world, and Kirito's memories of what happens inside are restricted. However, he is attacked by one of the murderers from GGO and wakes up inside UnderWorld, leaving him unable to remember how he ended up there or to log out, with his real self left in a comatose state.

Reki Kawahara wrote the first volume in 2002 as a competition entry for ASCII Media Works' Dengeki Game Novel Prize (電撃ゲーム小説大賞,Dengeki Game Shōsetsu Taishō?, now Dengeki Novel Prize), but refrained from submitting it as he had exceeded the page limit. He instead published it as a web novel under the pseudonym Fumio Kunori.[2] Over time, he added three further episodes and several short stories.[3][4] In 2008, he participated in the competition again by writing Accel World, this time winning the Grand Prize. Aside from Accel World, he was requested to get his earlier work, Sword Art Online, published by ASCII Media Works.[2] Kawahara agreed and withdrew his web novel versions.[4] Working with illustrator abec, the first volume was published in print on April 10, 2009,[5] and 15 volumes have been published as of August 9, 2014.[6] Kawahara also writes the Sword Art Online: Progressive series, which covers Kirito's adventures on the first few floors of Aincrad. The first volume of Progressive was released on October 10, 2012,[7] and two volumes have been released as of December 10, 2013.[8] The first volume of a light novel series based on Sword Art Online titled Sword Art Online: Alternative, written by Keiichi Sigsawa with illustrations by Kouhaku Kuroboshi, was published by ASCII Media Works on December 10, 2014.[9]

At their Japan Expo USA panel, Yen Press announced the rights to publish the light novels; the first volume was released on April 22, 2014.[10][11] Yen Press later announced their license of the Sword Art Online: Progressive series, which is scheduled for release in 2015.[12] The novels are also published in China, Taiwan, South Korea, and Thailand.[1] With more than 16.7 million copies in print worldwide, there are future plans for publications in France,[13] Germany, Italy, Austria, Switzerland, Vietnam and others.[1]

There are a number of dōjinshi, written by the series' original author Reki Kawahara under the pseudonym Fumio Kunori, titled Sword Art Online Material Edition(ソードアート・オンライン・マテリアル・エディション?).[14] An 80-page assemblage of some of the Material Edition volumes was published on February 13, 2011;[15] the latest release is Material Edition volume 14 on November 23, 2014.[16] The author has also created some other dōjinshi including Lisbeth Edition, Silica Edition and Pina Edition under cooperation with Kurusu Tatsuya from ponz.info.[17][18] It is reported that these dōjinshi gain traction from the involvement of the original author in its creation process, as well as from supplying more details on characters from the original work.[17]

There are eight manga adaptations of the series, all written by Reki Kawahara and published by ASCII Media Works. Sword Art Online: Aincrad(ソードアート・オンライン アインクラッド?), illustrated by Tamako Nakamura, was serialized in Dengeki Bunko Magazine between the September 2010 and May 2012 issues. Two tankōbon volumes of Aincrad were released on September 27, 2012.[19][20] A comedy four-panel manga, titled Sword Art Online.(そーどあーと☆おんらいん。?) and illustrated by Jūsei Minami, began serialization in the September 2010 issue of Dengeki Bunko Magazine. The first volume of Sword Art Online. was released on September 27, 2012.[21] A third manga, titled Sword Art Online: Fairy Dance(ソードアート・オンライン フェアリィ・ダンス?) and illustrated by Hazuki Tsubasa, began serialization in the May 2012 issue of Dengeki Bunko Magazine. The first volume of Fairy Dance was released on October 27, 2012;[22] the third volume was released on June 27, 2014.[23] The Aincrad and Fairy Dance manga have been acquired for release in North America by Yen Press.[10] The first volume of Aincrad was published on March 25, 2014.[11]

A spin-off manga starring Lisbeth, Silica, and Leafa, titled Sword Art Online: Girls Ops(ソードアート・オンライン ガールズ・オプス?) and illustrated by Neko Nekobyō, began serialization in the July 2013 issue of Dengeki Bunko Magazine.[24]Girls Ops was licensed by Yen Press in November 2014, who will release the first volume on May 19, 2015.[25][26] A manga adaption of Sword Art Online: Progressive, illustrated by Kiseki Himura, began serialization in the August 2013 issue of Dengeki G's Magazine. The manga ended serialization in the magazine's May 2014 issue and was transferred to Dengeki G's Comic starting with the June 2014 issue.[27] The Progressive manga adaption has been licensed by Yen Press, and the first volume is scheduled for release in January 2015.[12][28] A sixth manga, titled Sword Art Online: Phantom Bullet and illustrated by Kōtarō Yamada, had its first chapter serialized in the May 2014 issue of Dengeki Bunko Magazine, with following chapters being digitally serialized on Kadokawa's Comic Walker website. A seventh manga, titled Sword Art Online: Caliber and illustrated by Shii Kiya, began serialization in Dengeki G's Comic with the September 2014 issue.[29] An eighth manga, titled Sword Art Online: Mother's Rosario and also by Hazuki Tsubasa, will be based on the seventh volume of the novel series and serialized in Dengeki Bunko Magazine.

The opening theme song for the first 14 episodes is "crossing field" by LiSA[34] and the ending theme song is "Yume Sekai" (ユメセカイ?, lit. "Dream World") by Haruka Tomatsu.[35] From episode 15 onward, the opening theme is "Innocence" by Eir Aoi and the ending theme is "Overfly" by Luna Haruna. The anime has been licensed in North America by Aniplex of America[36] and an English-language dub premiered on Adult Swim's Toonami from July 27, 2013[37] to February 15, 2014.

The series was released by Aniplex of America in four DVD and Blu-ray sets, with special extras on the BD sets, between August 13 and November 19, 2013.[38]Manga Entertainment released the series on BD/DVD in the United Kingdom in December 2013,[39] whilst Madman Entertainment released the series in Australia[40] and the English-language version began airing on ABC3 on June 7, 2014.[41]Sword Art Online has been available on Netflix in North America since March 15, 2014.[42]

A year-end special, titled Sword Art Online Extra Edition, aired on December 31, 2013. The special recapped the previously aired anime series and included some new footage.[43] The special's main theme is "Niji no Oto" (虹の音,Sound of the Rainbow?) by Eir Aoi.[44]Extra Edition was streamed worldwide a few hours after its airing in Japan.[45] The two-hour-long special was available on Daisuki worldwide except for French-speaking areas, as well as China and Korea.[45] Daisuki offered subtitles in various languages such as English, Spanish, Portuguese, Italian, and German.[45] English-speaking countries, Mexico, Central and South America could also watch the stream on Crunchyroll.[46]

Extra Edition was also simulcast in Korea on Aniplus cable channel and in China on the LeTV streaming website.[46] French-speaking countries could watch on the Wakanim streaming website.[46] The Blu-ray Disc and DVD of Extra Edition was released on April 23, 2014 in Japan.[47] The limited edition included a Yui character song titled "Heart Sweet Heart" by Kanae Itō and an original side story written by Reki Kawahara titled "Sword Art Online Niji no Hashi" (ソードアート・オンライン 虹の橋,Sword Art Online Rainbow Bridge?).[47]

At the end of the special, the anime TV series was confirmed for a second season titled Sword Art Online II, which premiered on July 5, 2014.[48][49] The first 14 episodes of the second season is an adaptation of volumes five and six the light novels that cover the Phantom Bullet arc.[50] Episodes 15 to 17 cover the Caliber arc from volume 8 of the novels, with episodes 18 to 24 covering volume 7 of the novels, the Mother's Rosario arc. Premiere screening events of the second season were held in the United States, France, Germany, Hong Kong, Taiwan, Korea and Japan before the television premiere between June 29 and July 4, 2014.[51][52][53] The first opening theme is "Ignite" by Eir Aoi, and the first ending theme is "Startear" by Luna Haruna.[54] The second opening theme is "Courage" by Haruka Tomatsu, and the second ending theme is "No More Time Machine" by LiSA, with the third ending theme being "Shirushi" (シルシ?) by LiSA.

A stage event at the Dengeki Bunko Autumn Festival 2011 revealed that Reki Kawahara's light novels would get video game adaptations.[55] The first Sword Art Online adaptation, titled Sword Art Online: Infinity Moment(ソードアート・オンライン -インフィニティ・モーメント-,Sōdo Āto Onrain: Infiniti Mōmento?), was developed by Namco Bandai Games for the PlayStation Portable.[56] The game follows an alternate storyline, in which a glitch causes Kirito and the other players to remain in Sword Art Online despite defeating Heathcliff, and players from other VMMORPGs such as Leafa and Sinon get sucked into the game themselves.[57] The game was released in both regular and limited edition box sets on March 14, 2013.[58]

Sword Art Online: Hollow Fragment is a PlayStation Vita game released in Japan on April 24, 2014 rated C on the CERO rating scale.[59][60]Sword Art Online: Hollow Fragment takes place in the same alternative storyline as Sword Art Online: Infinity Moment,[61] and it includes all content of "Floor Clearing" from that previous game[62] with the addition of new unexplored "Hollow Area" of Aincrad.[63] The protagonist Kirito will cross swords with a mysterious player who would become one of the key characters in the game.[63] The game sold 145,029 physical retail copies within the first week of release in Japan, topping the Japanese software sales charts for that particular week.[64] The game had also been released in Taiwan by Namco Bandai Games Taiwan with Chinese and English subtitles.[65] A digital-only North American, European and Australian release was released in August 2014.

A third video game developed by Artdink[66] and titled Sword Art Online: Lost Song has been announced for a March 26, 2015[67] Japanese release on the PlayStation 3 and Vita platforms,[68][69] with an English version planned for release in Asia.[70] The game's producer revealed in October 2014 that the game will be an open-world action RPG featuring an original storyline, set within Alfheim Online, where characters are able to fly.[71]

A social network game called Sword Art Online: End World was released for Japanese feature phones and smartphones on February 28, 2013[72][73] with more than 1 million registered users.[74] Another freemium game for Android and iOS titled Sword Art Online: Code Register launched in 2014, and has had over 3,000,000 users downloaded the game.[75] Another game called Sword Art Online: Progress Link designed for the Mobagebrowser game platform on smartphones was released on February 10, 2015.[76]

Kirito, Asuna and Leafa appear in Dengeki Bunko Fighting Climax, a fighting game by Sega featuring various characters from works published under the Dengeki Bunko imprint.[77][78] A browser game titled Sword Art Quest and its sequel smartphone game Sword Art Quest II[79] provide challenges to users to upgrade their characters to receive rewards.[80] There is also a paid Android game titled SAO -Log Out- that users can download and play with characters from the series and obtain wallpapers from it.[81]

According to Oricon, Sword Art Online was the top selling light novel series of 2012, with eight volumes figuring among the top selling light novels.[82][83] It was ranked first in the 2012 and 2013 Kono Light Novel ga Sugoi! rankings, as well as top ten placement in 2011, 2014 and 2015.[84][85][86][87][88] Richard Eisenbeis of Kotaku hails Sword Art Online as the smartest series in recent years, praising its deep insight on the psychological aspects of virtual reality on the human psyche, its sociological views on creating a realistic economy and society in a massively multiplayer online game setting, and the writing staff's ability to juggle a wide variety of genres within the series.[89] Eisenbeis particularly noted how the romance between Kirito and Asuna is explored bringing "definition to exactly what love is like in a virtual world." However, at the time of this preliminary review, he had only watched the first 12 episodes of the series. He has since gone on to review the second half of the series, lauding its excellent use of plot twists and praising its well written and believable villain. However, he felt that some of the initial positive aspects of the series were lost in the second half, such as the focus on psychological repercussions and social interactions that could be realistically seen in an online game. Criticism was also levied on the aspect of turning Asuna into a damsel in distress, stating that a female lead as strong as her was "reduced to nothing but the quest item the male lead is hunting for." Eisenbeis closes his review of the series by stating in regards to the two halves, "Both, however, are enjoyable for what they are."[90]

Rebecca Silverman of Anime News Network has criticized the series as having pacing problems and "sloppy writing".[91] Theron Martin criticized the story as struggling "to achieve and maintain the level of gravitas that life-or-death danger should have", while calling it unwilling to commit to Kirito's "lone wolf" image.[92] DeviceCritique explains that Sword Art Online influences the virtual reality market to grow, and references the Oculus Rift as a prime example of the starting point of virtual reality. It also praises Sword Art Online for exploring the psychological and social aspects of virtual reality gaming.[93] Adam Facey of The Muse criticized the series, among others, as being sexist and the female characters as being overly sexualized.[94]